Delta squib circuit

ABSTRACT

An electroexplosive device disposed for energization for creating a spark flame and/or gaseous discharge which is utilized to perform a work function such as igniting the propellant igniter in a rocket to initiate launch thereof.

United States Patent Betts Oct. 3, 1972 I DELTA SQUIB CIRCUIT [72] Inventor: Robert E. Betts, 8107 Hogan Dr.

S.E., Huntsville, Ala. 35802 [22] Filed: Nov. 9, 1970 [21] Appl. No.: 87,755

[52] US. Cl. ..l02/28 R [5] Int. Cl. ..F42c 19/12 [58] Field of Search 102/28, 28 M, 28 EB [56] References Cited UNITED STATES PATENTS Przybylik et al 102/28 Friese-G reene et al 102/28 EB 3/1964 Boggs et a1. 102/28 7/1962 Clark ..l02/28 Primary Examiner-Verlin R. Pendegrass Attorney-Harry M. Saragovitz, Edward J. Kelly, Herbert Ber] and Harold W. Hilton ABSTRACT An electroexplosive device disposed for energization for creating a spark flame and/or gaseous discharge which is utilized to perform a work function such as igniting the propellant igniter in a rocket to initiate launch thereof.

4 Claims, 2 Drawing Figures PATENTEDocr 3 m2 Robert E. Behs,

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Mid 4% BACKGROUND OF THE INVENTION composed of small charges of pyrotechnics or explosive powders that can be easily ignited by a spark discharge or a hot wire which provides sufficient temperature to ignite the igniter, in turn igniting the main propellant charge.

Some conventional initiators use a single bridge wire connected across a pair of terminals and when an electrical potential is applied across the terminals, the bridge wire is heated or exploded to provide the impetus for the desired reaction. Other electroexplosive devices use double bridge wires in parallel or series circuit arrangements. A conventional parallel circuit includes a first bridge wire connected between a first pair of terminals and a second bridge wire disposed in parallel relation with the first wire and connected between a second pair of terminals. In this arrangement, an electrostatic difference between the two circuits may cause inadvertant ignition by sparking between the two circuits through the pyrotechnic. Another conventional type of electroexplosive device utilizes a first bridge wire connected between a first and second terminal, a second bridge wire connected between the second and a third terminal to provide a series circuit. However, difficulty arises in the use of this type of circuit in that the first and third terminals are not common for a series circuit and pin orientation must be maintained to insure proper connection to the firing circuit.

The device of the present invention includes a squib utilizing a Delta circuit arranged in series-parallel relation to overcome the above noted difficulties.

SUMMARY OF THE INVENTION An electroexplosive device having a trio of terminals extending externally of a body enclosing an igniter charge. A triangular circuit (Delta circuit) includes a plurality of bridge wires connected across the terminals, in the interior of the body, adjacent a propellant charge mounted in the body. The Delta circuit includes a first bridge wire connected between the first and second terminals and a second bridge wire connected between the second and third terminals, and a third bridge wire connected between the third and first terminals, to provide a series-parallel Delta circuit.

It is, therefore, an object of the present invention to provide an electroexplosive device having a combined series-parallel circuit therein.

Other objects and advantages of the present invention will be more readily apparent from the following description and drawing.

2 BRIEF DESCRIPTION OF THE DRAWIN FIG. 1 is a elevational sectional view of an igniter squib utilizing the Delta circuit of the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1 illustrating the Delta circuit of my invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1, an igniter squib 10 includes a housing 12 having an end closure 14 at one end 15 thereof and an insulating member 16 carried in the housing adjacent a second end 17 thereof. A cavity 18 is formed intermediate end closure 14 and an interior surface 19 of insulating member 16. Cavity 18 is provided therein with a pyrotechnic pelleted charge 20 which encloses a pyrotechnic powder charge 21, and a plurality of bridge wires 22, 24 and 26 (FIG. 2) having a bead or charge of lead azide or the like coated thereon.

To provide for external connection to bridge wires 22, 24 and 26, the insulating member 16 is provided with a plurality of apertures 28, 30 and 32 through which a plurality of terminals 34, 36 and 38 extend. Bridge wires 22, 24 and 26 are connected to the terminal ends 40, 42 and 44 of terminals 38, 36 and 34 respectively.

As shown in FIG. 2, terminals 34, 36 and 38 are in a triangular arrangement having a first bridge wire 22 connected to terminals 36 and 38, the second bridge wire 24 is connected to terminals 36 and 34, and a third bridge wire 26 is connected to terminals 38 and 34. Thus, any two pins connected externally of the squib forms a series-parallel circuit.

Body 12 includes a hexagonal base portion 46 and a threaded portion so that the initiator may be easily installed in threaded relation in the igniter. The hexagonal portion permits facile assembly by a wrench or the like.

It should be obvious, therefore, that applicant has provided a squib circuit which lends itself to facile assembly in an igniter circuit of rockets and the like, in that any two pins of applicants device may be connected external to the squib to form a series-parallel circuit without regard to pin orientation. Additionally, since it is sometimes necessary to check the squib devices prior to installation and since low resistance wires are used in such circuits, the ability to detect a broken wire by simple resistance measurements is made easier in the present device since the resistance change in Delta circuits are greater than conventional circuits.

lclaim:

1. An electroexplosive initiator comprising:

a. a housing enclosing a propellant charge;

b. three of terminals each having a first end carried in said housing adjacent said propellant charge and a second end extending out of said housing; and,

c. bridge wire means connected to said first end of said terminals in a Delta circuit relationship.

2. A device as set forth in claim 1 wherein said three terminals are mounted in said housing in a triangular arrangement and wherein said bridge wire means are a low resistance wire connected between said terminals.

lating member mounted in said body adjacent the second end thereof and in spaced relation with said closure plate to form a cavity therebetween, said terminals extending into said body through said insulating members, and, said bridge wires being connected adjacent the ends of said terminals which terminate in said cavity. 

1. An electroexplosive initiator comprising: a. a housing enclosing a propellant charge; b. three of terminals each having a first end carried in said housing adjacent said propellant charge and a second end extending out of said housing; and, c. bridge wire means connected to said first end of said terminals in a Delta circuit relationship.
 2. A device as set forth in claim 1 wherein said three terminals are mounted in said housing in a triangular arrangement and wherein said bridge wire means are a low resistance wire connected between said terminals.
 3. A device as set forth in claim 2 wherein said bridge wire means includes a first bridge wire connected between a first and second of said three terminals, a second bridge wire connected between said second and the third of said three terminals, and, a third bridge wire connected between said third and said first terminals.
 4. A device as set forth in claim 3 including a closure plate disposed adjacent a first end of said body, an insulating member mounted in said body adjacent the second end thereof and in spaced relation with said closure plate to form a cavity therebetween, said terminals extending into said body through said insulating members, and, said bridge wires being connected adjacent the ends of said terminals which terminate in said cavity. 